An electron probe microanalyzer equipped with a wavelength-dispersive spectrometer is disclosed, for example, in U.S. Pat. No. 3,914,605. Electron probe microanalyzers equipped with an energy-dispersive x-ray spectrometer are disclosed, for example, in U.S. Pat. Nos. 4,253,154, No. 4,697,080, and No. 4,724,320. In these electron probe microanalyzers, an electron beam is caused to impinge on the surface of a specimen. The characteristic x-rays emanating from the specimen are detected by a wavelength-dispersive or energy-dispersive x-ray spectrometer, and an x-ray spectrum is displayed according to the result of the detection. Thus, the elements included in the specimen are identified according to the spectrum.
The wavelength-dispersive spectrometer and the energy-dispersive spectrometer have different features. In particular, the wavelength-dispersive x-ray spectrometer exhibits high resolution in terms of wavelengths, but it cannot easily remove higher-order x-rays it entails. On the other hand, the spectrum obtained by the energydispersive spectrometer has no higher-order x-rays, but shows poor energy resolution. Especially, it cannot easily detect quite light elements, for example, in the range from beryllium to fluorine.
Accordingly, it is the common practice to detect x-rays with only a wavelength-dispersive x-ray spectrometer (WDS) or an energy-dispersive x-ray spectrometer (EDS). The obtained WDS or EDS spectrum is displayed on a display device to identify elements. When elements are identified based on only a WDS spectrum, the operator might misidentify the included elements because of higher-order x-rays. On the other hand, when elements are identified based on only an EDS spectrum, peaks tend to overlap due to poor energy resolution. As a result, the operator might overlook some elements included.
In view of these problems, the present inventors have already proposed an electron probe microanalyzer equipped with a wavelength-dispersive x-ray spectrometer and also with an energy-dispersive x-ray spectrometer in U.S. patent application Ser. No. 215,222 entitled "Spectrum Display Device For X-Ray Microanalyzer Or The Like". In this proposed microanalyzer, two kinds of spectra are displayed, based on the x-rays obtained from the same specimen region under investigation by the two kinds of spectrometers. An element-designating means is provided to permit one to designate any desired chemical element. Further, there is provided a means which superimposes markers or cursors on the displayed spectra to indicate the energies or wavelengths of the characteristic x-rays emanating from the element designated by the element-designating means. The present invention pertains to improvements over this proposed microanalyzer.